Many beverages like espresso and other coffee beverages, milk beverages, chocolate beverages are prepared by mixing a beverage soluble powder with a diluent. Mixing devices are known for speedier preparation of such beverages by mixing the beverage soluble powder with the diluent, such as water. These devices can comprise a dissolution chamber in which the soluble component and the diluent are fed. The diluent can be introduced into the dissolution chamber in order to create a whirlpool to efficiently dissolve the soluble powder in the hot water or the hot diluent can be introduced under the form of jets that provides mixing, dissolving and frothing. The mixture can also eventually be frothed by a whipper in the dissolution chamber to reconstitute the beverage and produce foam. The beverage is then usually evacuated into a receptacle for drinking. These devices can also mix the beverage soluble powder with the diluent in a drinking cup, usually a single use cup. In that case the soluble food component is introduced in the cup and the diluent is introduced under the form of jets that provides mixing, dissolving and/or frothing.
Whatever the way the powder and the diluent are mixed together the beverage soluble powder is usually stored in a container placed above the dissolution chamber opened mouth and a dosing device like a screw or an auger doses and delivers the beverage soluble powder which falls in the dissolution chamber or the drinking cup. Diluent is simultaneously fed to the dissolution chamber so that dissolution occurs. Several issues exist with such a configuration.
First the soluble powder frequently comprises fine particles which can easily flies when powder falls from the container outlet to the dissolution chamber. These fine particles dirty the internal housing of the dispenser.
Secondly, the vapour and humidity generated during the beverage preparation in the dissolution chamber or the drinking cup raises and surrounds the container outlet. If another beverage is rapidly prepared after another one then the new dose of powder delivered by the container reacts partially with the humidity and creates non hygienic deposits around the outlet. After a period of time, this process can lead to an accumulation of moisture on the discharge port of the container. As the quantity of soluble powder accumulating on discharge port increases over time, the outlet becomes increasingly constricted. Ultimately, this can result in the outlet becoming completely clogged, which results in the complete failure of the dosing device. Additionally, the soluble powder adhering to the discharge port is constantly moistened by the rising vapours. This can result in the soluble powder caking and even turning mouldy or growing harmful bacteria after extended use. This may lead to the dosing device rendering the powder ingredient inconsumable.
Consequently it has been proposed to close the discharge port when no powder is dosed and when the powder is mixed with water in the dissolution chamber.
EP-A1-331 271 has proposed a dispenser with a powder container comprising a metering screw, drivable by an electromotor, the metering screw being surrounded by a tubular member. The container comprises a closing valve at the discharge end of the metering screw tube, said closing valve being activated by a driving pin extending through the longitudinal axis of the metering screw and displaceable by a solenoid connected in the starter of the electromotor. Yet the position of the driving pin through the longitudinal axis of the metering screw is complex. It is necessary to manufacture of a specific metering screw with a central void dedicated to the position of the driving pin inside.
In U.S. Pat. No. 4,610,378 a container for food powders, particularly for automatic beverage distributing machines, comprises a screw member revolving inside a duct bearing a delivering mouth which is closed, in non-working conditions, by a plate closing member. The closing member is opened by the end of the screw member during its rotational motion at the dosing operation. During said dosing operation the delivering mouth is successively opened and closed which does not enable a rapid and fluid dosing and powder is compressed.
WO 2014/115061 has proposed an extruder for use in a dispenser of loose product that is substantially insensitive to operation in a moist environment. The extruder includes a screw that is both rotatably and translatably received in a bore of the dispenser such that it is axially movable along the longitudinal axis of the bore between a first position and a second position. The extruder includes a sealing device that is configured to releasably fluidtightly seal a portion of the bore interconnecting the product inlet and the product outlet in dependence of the axial position of the screw. The configuration of the extruder is such that, in said first axial position of the screw, the sealing device fluidtightly seals the portion of the bore interconnecting the product inlet and the product outlet. In the second axial position of the screw, in contrast, the sealing device does not fluidtightly seal the portion of the bore interconnecting the product inlet and the product outlet, and rotation of the screw effects the continuous extrusion or discharge of loose product, supplied at the product inlet, from the product outlet. Consequently humidity due to the hot water used to prepare beverage cannot rise in the discharge opening of the extruder since the discharge opening can be closed during beverage preparation.
Although this extruder solves the problem of humidity arising in the discharge opening during beverage preparation, this extruder does not take into account the problem of keeping the dosing of loose product, like powder, consistent. Yet the consistent preparation of a beverage is essential with a beverage dispenser. Customers expect to get always the same beverage when they order the same beverage at different times with the same dispenser. An important factor of control of a beverage consistency consists in a consistent dosing of the soluble beverage powder during beverage preparation. The extruder of WO 2014/115061 does not enable a consistent dosing because the back rotation of the screw seems to create a void in the outlet of the extruder which affects the following dosing operation since no loose product is dispensed by the extruder at the beginning of its activation. Moreover this extruder is made of complex mechanical pieces which increase its costs of production.
A solution has been proposed in EP 1 176 402 in which the outlet of the container is opened only when the powder is dosed and delivered in order to prepare a beverage and is closed the rest of the time. Consequently humidity is avoided from reaching the outlet of the powder container and from entering inside the container outlet. The risk of clogging in the container outlet is limited.
Yet the way the above solution is implemented presents some defaults. In particular the outlet is closed by a sealing element operated by a gear train comprising intermeshing gears connected to a transmission rod which is in turn connected to a motor. The gear train is positioned close to the container outlet and is not protected again humidity rising from the dissolution chamber or the drinking cup. Consequently if powder fines flies around the powder outlet and deposit on the gear train, the reaction of powder fines and humidity could cause the failure or blockage of the gear train. Actually the dispenser described in EP 1 176 402 is a relatively small dispenser that is not conceived for significant preparation of beverages during the whole day.
Nowadays cleaning is a key aspect of beverage dispensers. Actually cleaning is a time consuming task. There is need for decreasing the time for the cleaning operation to limit the period of time during which the dispenser is not operable. Moreover people operating the dispensers are less and less trained, so there is a need for a dispenser that can be cleaned in a very easy way.
There is a need for improving powder container outlet closure and improving cleaning of the dispenser.
An object of the invention is to address at least some of the drawbacks of the prior art dispensers or at least to provide an alternative thereto.
It would be advantageous to provide a beverage dispenser presenting a powder container of which outlet prevents humidity from rising in the container.
It would be advantageous to provide a beverage dispenser presenting a powder container and a device for alternatively closing and opening the powder container outlet.
It would be advantageous to provide a beverage dispenser presenting a powder container and a device for alternatively closing and opening the powder container outlet, said device being protected from humidity.
It would be advantageous to provide a beverage dispenser presenting a powder container and a device for alternatively closing and opening the powder container outlet, wherein the mechanism for closing and opening the powder container outlet does not complicate the cleaning operation of the dispenser.